December 12, 2015

"Take any two fundamental particles — of any mass and any of the forces through which they interact — and find that gravity is literally forty orders of magnitude weaker than all the other known forces in the Universe."

'Warped Extra Dimensions... pioneered by the aforementioned Lisa Randall along with Raman Sundrum — holds that gravity is just as strong as the other forces, but not in our three-spatial-dimension Universe. It lives in a different three-spatial-dimension Universe that’s offset by some tiny amount — like 10^(–31) meters — from our own Universe in the fourth spatial dimension. (Or, as the diagram above indicates, in the fifth dimension, once time is included.) This is interesting, because it would be stable, and it could provide a possible explanation as to why our Universe began expanding so rapidly at the beginning (warped spacetime can do that), so it’s got some compelling perks.

'What it should also include are an extra set of particles; not supersymmetric particles, but Kaluza-Klein particles, which are a direct consequence of there being extra dimensions. For what it’s worth, there has been a hint from one experiment in space that there might be a Kaluza-Klein particle at an energy of about 600 GeV, or about 5 times the mass of the Higgs. Although our current colliders have been unable to probe those energies, the new LHC run should be able to create these in great enough abundance to detect them… if they exist.

'The existence of this new particle, however, is by no means a certainty, as the signal is just an excess of observed electrons over the expected background. Still, it’s worth keeping in mind as the LHC eventually ramps up to full energy; almost any new particle that’s below 1,000 GeV in mass should be within range of this machine.'